1. Field of the invention
The present invention relates to a novel thiazolecarboxamide derivative. More particularly, the present invention relates to a novel 2-aminothiazolecarboxamide derivative represented by the following general formula (I): ##STR2## in which R.sup.1 and R.sup.2 independently of one another represent hydrogen, (C.sub.1 -C.sub.5)alkyl, (C.sub.1 -C.sub.5)haloalkyl, (C.sub.3 -C.sub.6)alkenyl, (C.sub.3 -C.sub.6)alkynyl, (C.sub.3 -C.sub.6)cycloalkyl, ##STR3## or phenyl or benzyl, each of which can be substituted with halogen, (C.sub.1 -C.sub.3) alkyl or nitro;
R.sup.3 represents (C.sub.1 -C.sub.3)alkyl or (C.sub.1 -C.sub.3)haloalkyl;
R.sup.4 represents 2-thienyl, 3-thienyl, 2-furyl, 3-furyl, phenyl, or benzyl, each of which can be substituted with halogen, (C.sub.1 -C.sub.6)alkyl or nitro;
R.sup.5 represents cyano or thiocarbamoyl; and
R.sup.6 represents (C.sub.1 -C.sub.6)alkyl, (C.sub.3 -C.sub.6)alkenyl, (C.sub.3 -C.sub.6)cycloalkyl, or phenyl or benzyl, each of which can be substituted with halogen, (C.sub.1 -C.sub.3)alkyl or nitro.
The present invention also relates to a process for preparing the compound of formula (I), as defined above, and use of the compound of formula (I) for controlling phytopathogenic organisms.
2. Background Art
Fungicidal agents against Oomycetes occupy approximately 25% of the total fungicide market and have built up a unique market because Oomycetes is characterized by mycelium having no ergosterol biosynthesis mechanism. At the present time, conventional non-systemic fungicidal agents, for example, captan, captafol, dithiocarbamate, chlorothalonil, etc., have been widely used for controlling Oomycetes. However, it has been disclosed that such non-systemic fungicidal agents have only a preventive activity against Oomycetes but have serious toxic effect. In the 1970's acylalanine-based fungicidal agents were developed as a systemic fungicide. However, it has been also reported that the resistance of Oomycetes to such systemic fungicides becomes gradually aggravated. Further, recently the field of fungicidal agents against Oomycetes has not achieved any remarkable development. Accordingly, the development of a novel fungicide against Oomycetes which has a high fungicidal activity and a low toxicity has been strongly desired.
To satisfy such a requirement, in the latter half of the 1980's dimethomorph was developed and reported as an agent for controlling causative organisms of late blight and downy mildew in fruit trees and potatoes. In addition, for disinfecting cereal seeds and controlling causative organisms of rust and smut metsulfovax represented by the following formula (II) was developed (see S. African Patent No. 67 06,681): ##STR4##
Thereafter, the following thiazolecarboxamide-based compounds have also been proposed as an effective substance having fungicidal activity against Oomycetes:
1) Heterocyclic carboxamide compounds represented by the following general formula (see European Patent No. 268,892): ##STR5## in which A denotes pyrazolyl, imidazolyl, thiazolyl, isothiazolyl, oxazolyl or isoxazolyl, each of which has substituent(s),
B denotes alkoxy, alkylthio, imidazolyl, pyrazolyl, furyl or thienyl, and
D denotes cyano, thiocarbamoyl or acylthiocarbamoyl.
Among the above-identified heterocyclic carboxamide compounds, the compound having the following formula (III) has been proposed as a typical effective substance: ##STR6## and has been reported as having a significant preventive and curative effects on Pseudoperonospora cubensis, which is the causative organism of downey mildew in cucumber, at a concentration of 100 ppm.
2) Thiazolecarboxamide compounds represented by the following general formula (see European Patent No. 292,937 and Japanese Laid-open Patent Publication No. (Hei) 4-154704 (1992)): ##STR7## in which R.sup.1 and R.sup.2 represent hydrogen or (C.sub.1 -C.sub.3)alkyl, and
R.sup.3 represents 2-furyl, 3-furyl, 2-thienyl or 3-thienyl.
Among the above-identified thiazolecarboxamide compounds, the compound having the following formula (IV) has been proposed as a typical effective substance: ##STR8## and it has been reported that the compounds (IV-1) and (IV-2) prevent tomato late blight by 70% and 80%, respectively at a concentration of 25 ppm.
3) Thiazolecarboxamide compounds represented by the following general formula (see European Patent No. 313,091): ##STR9## in which one of X and Y represents S and the other represents C,
Z represents cyano or thiocarbamoyl,
R.sup.1 and R.sup.2 independently of one another represent hydrogen, halogen, (C.sub.1 -C.sub.6)alkyl, halomethyl or phenyl, and
R.sup.3 represents (C.sub.2 -C.sub.6)alkenyl, (C.sub.2 -C.sub.4)haloalkenyl, furyl, thienyl, (C.sub.1 -C.sub.4)alkoxy, (C.sub.1 -C.sub.4)alkylthio, (C.sub.3 -C.sub.5)alkynyloxy, (C.sub.3 -C.sub.5)alkynylthio, pyrazolyl, or phenyl which can be substituted with halogen.
4) Thiazolecarboxamide compounds represented by the following general formula (see European Patent No. 434,620): ##STR10## in which R.sup.1 and R.sup.2 independently of one another represent hydrogen, alkyl, cycloalkyl (which can be substituted with methyl or methylthio) or --CH.sub.2 XR.sup.4,
R.sup.3 represents furyl or thienyl,
R.sup.4 represents alkyl, alkenyl or alkynyl (each of which can be substituted with halogen or alkoxy), or phenyl or benzyl (each of which can be substituted with halogen, alkyl, alkoxy, trifluoromethyl or nitro), and
X represents oxygen or sulfur atom.
As the typical effective substance of the above-identified compounds, the compound having the following formula (V): ##STR11## was proposed and it has been reported that the compound of formula (V) controls tomato late blight by 90% or more at a concentration of 60 ppm.
The above exemplified, effective thiazole carboxamide compounds have a certain degree of fungicidal activity and also a low toxicity. However, they have a disadvantage in that their fungicidal activities are lower than that of dimethomorph which was developed and commercialized in the latter half of the 1980's.
Thus, the present inventors have extensively studied to develop a new compound having a high fungicidal activity and a low toxicity. As a result, we have identified that a certain thiazolecarboxamide derivative having an amino group attached to the 2-position of the thiazole ring, i.e. a novel 2-aminothiazolecarboxamide derivative having the general formula (I), as defined above, shows a potent fungicidal activity which is higher than those of the presently known thiazolecarboxamide compounds and dimethomorph, and also has a systemic activity and a curative activity as well as a preventive activity, and then completed the present invention.
Therefore, it is an object of the present invention to provide a novel 2-aminothiazolecarboxamide derivative having the general formula (I), as defined above.
It is a further object of the present invention to provide a process for preparing the 2-aminothiazolecarboxamide derivative of formula (I).
It is another object of the present invention to provide a use of the 2-aminothiazolecarboxamide derivative of formula (I) as an agent for controlling plant diseases caused by typical phytopathogenic organisms of Oomycetes.
The more pertinent and important features of the present invention have been outlined above in order that the detailed description of the invention which follows will be better understood and that the present contribution to the art can be fully appreciated. Those skilled in the art can appreciate that the conception and the specific embodiment disclosed herein may be readily utilized as a basis for modifying or designing other structures for carrying out the same purpose of the present invention. Further, those skilled in the art can realize that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the claims.